1. Field of the Invention
The invention concerns generally the technical field of transporting sheet-like workpieces on a manufacturing line. Especially, the invention concerns the transporting of a series of printed workpieces between a stacker and a cutter in a manufacturing process where the series may be short and irregular.
2. Description of Related Art
A package manufacturing line typically comprises a printer, a coater, a stacker, and a cutter in this order. Planar, sheet-like workpieces are fed into the printer. Printed workpieces receive a coating in a coater, after which they are stacked in a stacker to wait for cutting. The cutter is typically a die cutter, in which the cutting tool needs to be changed between series of workpieces that are to be cut differently. Therefore it is advantageous that the stacker makes separate stacks of the different series. Each stack is transported to the cutter and placed in an automatic feeder section when the appropriate tool is in place and cutting can begin.
The International Patent Application Publication WO 2009/130393 A1 and corresponding U.S. Pat. No. 8,493,421 disclose a modular, automatic conveyor, which may comprise branching and combining points, and which may even combine the flows coming from parallel printing and coating units to a common cutter. Practice has shown that despite its many advantages, the conveyor disclosed in these documents does not offer optimal possibilities for arranging the handling of different series, especially when there is large fluctuations in the sizes of consecutive series.